#include does not work!

Hi all,
as a preparatory exercise in studies I created the following source code:

#include<Euro_535.h> // Registernamen

void Main (void)
{
        int zaehler;
        int k;
        int entprellzeit;
        k = 0;
        entprellzeit=2000;

        while(1)
        {
                if(Taster_1=0)
                {
                        for(k=0; k<entprellzeit; k++)
                        while(Taster_1=0)
                        zaehler++;
                        if(zaehler>=3)
                        {
                        Leuchte_1=0;
                        }
                }
                if(Taster_2=0)
                {
                zaehler=0;
                Leuchte_1=1;
                }
        }
return;
}

when translating the file, 6 errors occure and I don't know how to handle them.
error 318: can't open file 'Euro_535.h'
... do I have to include the file to target? I already tried it, but it doesn't work...

errors with Taster_1 Taster_2 Leuchte_1 : undefined identifier??
...But these variables are defined in the headerfile! so why is this error message appearing??...

I hope someone can help me clarifying these "beginners" problems.

Thank U in advance,
Tom